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Add more type examples for the typeof operator in JavaSccript #3291

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Add more type examples for the typeof operator in JavaSccript #3291

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7 changes: 6 additions & 1 deletion packages/documentation/copy/en/get-started/TS for JS Programmers.md
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Original file line number Diff line number Diff line change
Expand Up @@ -159,11 +159,16 @@ To learn the type of a variable, use `typeof`:
| string | `typeof s === "string"` |
| number | `typeof n === "number"` |
| boolean | `typeof b === "boolean"` |
| null | `typeof null === "object"` |
| undefined | `typeof undefined === "undefined"` |
| object | `typeof o === "object"` |
| function | `typeof f === "function"` |
| array | `Array.isArray(a)` |
| symbol | `typeof s === "symbol"` |
| bigint | `typeof b === "bigint"` |

For example, you can make a function return different values depending on whether it is passed a string or an array:
You might be wondering why `typeof null` is `object` in JavaScript, and that is an historical accident which will be mentioned again later.
Back to unions, you can make a function return different values depending on whether it is passed a string or an array:

<!-- prettier-ignore -->
```ts twoslash
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